The invention relates to toilets, and more particularly to hinges for toilet seats and/or covers.
A typical toilet seat hinge includes a hinge post, separate hinge leaves, and a pintle or pintles connecting the hinge leaves to the hinge post. The hinge members and pintles form crevices that can harbor dirt, moisture and germs. The hinge leaves are typically attached to the toilet seat by wood screws which penetrate the surface of the toilet seat. The screw threads form a conduit which, by capillary action, may draw dirt and moisture into the permeable core of the toilet seat. Also, wood screws themselves are vulnerable to corrosion, particularly from urine and cleaning materials and disinfectants. Furthermore, the wood screws can discolor surrounding material, and their heads and slots or keys harbor dirt.
The hinge posts of conventional hinge assemblies are attached to a toilet bowl with nuts and bolts. The smooth surface of the toilet bowl offers very little resistance to rotation of the mounting parts. At the same time, only limited clamping pressure can be applied to the toilet bowl because the china will crack if the nuts and bolts are overtightened. Therefore, lateral pressure applied to the front of the toilet seat tends to move the hinge mounting parts so they pivot about their center. Movement of the hinge leaves about the screw holes, movement of the hinge parts about the hinge pintles and the above-described movement of the mounting parts results in substantial possible lateral movement of the toilet seat. The front edges of a toilet seat are supported on the toilet bowl by bumper pads that rest on the bowl rim. Only a relatively small, flat surface exists on the bowl rim so that, with a small amount of lateral movement of the front of the toilet seat, the bumpers will slip over the edge of the rim. This problem is exacerbated by the weight of a person on the toilet seat.
Carlson U.S. Pat. No. 3,277,500 discloses the use of a pair of membrane or "living" hinges for a toilet seat and cover. Carlson's hinges magnify all of the above-described problems. First, Carlson utilizes wood screws to secure his hinge leaves to the toilet seat and cover. Second, the distance between the point at which Carlson's hinges are connected to the toilet seat and the point at which the hinges are connected to the toilet bowl is so great that, due to the low flexural modulus of the materials used by Carlson, the hinge leaves themselves are susceptible to considerable flexing.